Governor



July 20; 1943. A. KALIN 2,325,009

e ovrmuoa Griginal Filed March 26, 1941 3 Sheets-Sheet 1 INVENTOR ALBERTKALIN ATTORNEY A. KALIN GGVERNQR Griginal Filed March 26, 194i 3Sheets-Sheet 2 ATTORNEY July 20, 1943. A. KALIN GOVERNOR Original FiledMarch 26, 1941 3 Sheets-Sheet 3 Fag-3 "WEN-ken ALBERT KALIN ATTORNEYPatented July 20, 1943 UNITED STATES PATENT Divided and this applicationSeptem ber 10, 1941, Serial No. 410,284

3 Claims.

This application is a division of my application Serial No. 385,228flied March 26, 1941. In the parent application there is shown agovernor for prime movers and other machinery substantially according tomy Patent 2,219,229 issued October 22, 1940. Said governor, as in thepatent, operates through a hydraulic fluid system including aservo-motor piston and cylinder, under the control of a pilot valve andweighing means, to regulate for instance speed of a Diesel engine tohold the speed constant notwithstanding variations in load on theengine.

The governor has an accumulator system operable automatically tomaintain constant posi tive pressure in the hydraulic system so long asthe governor and a suitable pumping system arranged to supply thegovernor with hydraulic fluid are driven by the-engine. The accumulatoris spring loaded for operation such as to maintain the desired constantpressure in event of overdelivery by the pumping system and when theengine has been idle for a short time (sometimes a few seconds) thepressure is usually reduced to a low value by operation of theaccumulator spring or springs and seepage of hydraulic fluid pastvarious coacting working parts, notwithstanding close clearances betweensaid parts. The hydraulic fluid in shutting down, as in the governorshown in the parent application, may purposely be dumped from theregulating servomotor and connected fluid passages, requiring rechargingbefore the engine can be restarted. Upon restarting, because of initiallack of working hydraulic pressure, at least some time must elapsebefore the governor can take full control of the engine. This sometimesmakes the operation of starting of the engine take longer than it should(e. g. more time than available in certain circumstances) and usuallyresults in waste of starting power (e. g. air supply),

The provision of means separate from the governor to supply hydraulicfluid to the governor at suitable pressure in order to meet the problemoutlined above is already known in the art; but, so far as I know, ithas not previously been proposed to provide boosting hydraulic pressuremeans as part of the governor mechanism. The present arrangementutilizes air (or other elastic fluid maintained under pressure forstarting pur poses) in a special servo-motor, built into themultaneously with or prior to performing the op- The mechanismcomprising the principal subject matter of this application will usuallybe referred to herein for convenience as a booster-servo.

Another object is to provide a booster-servo cylinder and pistonmechanism having shock absorbing means operable in event there is aninsufficient supply of hydraulic fluid in the boosterservo cylinder'when operation of the booster- I servo takes place0r in event theactuating (e. g. air) pressure for the booster-servo is excessiveto dampor cushion said operation.

A further object is to provide a booster-servo mechanism arranged toenable air at high pressure to be used to build up initial oil pressurein a governor, wherein the air and oil have no possibility of becomingmingled in a manner such as might cause improper operation of the governor or an explosion-as will be more fully explained later herein.

Other objects and advantages of the invention will become apparent fromthe following description of a preferred form thereof, as shown in thedrawings, in which:

Fig. 1 is a central sectional view of a speed governor incorporating theinvention; Fig. 2 is a plan view of the governor, and Fig. 3 is avertical sectional view thereof taken as indicated at 3--3 on Figs. 1and 2.

In the governor mechanism shown herewith as one type of governor onwhich the booster-servo mechanism may be used, I (Figs. 1 and 3) is abase adapted to be mounted on an engine to be governed, 2 a power casesurmounting the base, 3 a regulating servo-motor cylinder block attachedas at one side of the power case, and 4 a speeder case for the speedresponsive or weighing mechanism and adjusting means therefor.

A shaft Hi, to be drivingly coupled to the engine, is supported in thebase as by a bearing H above which is an oil seal I2. The shaft carriesa pump gear iii in a suitable pump chamber formed in the power case asshown in my said patent (the cooperating gear not being shown herein),and the pump is provided with a suitable reversible valve system, one ofeach of two pairs of valves being indicated at 23 and 24 respectively,for enabling the pump to draw hydraulic fluid from a sump S in the powercase and speeder case (normal fluid level at L) which communicates witha pump inlet chamber It in the base.

During rotation of the shaft III by the engine, hydraulic fluid ismaintained under constant operating pressure in ducts or passages I5, l6and ii in cooperation with spring loaded accumulators (not shown)located at opposite sides of the passage l6 and communicating with theduct I6 as by cross passages one of which is indicated at H! (leftFig.1). The accumulators maintain uniform pressure in the ducts l5, I6 and ll in the event of overdelivery by the pumpexcess fluid being dischargedto the sump essentiallyi, as in the arrangement shown in said patent.Hydraulic fluid supplied to and maintained at the bore I! under constantpressure is controlled by operation of a pilot valve (plunger 20, sleeve2| and other elements to be described later) to efiect movement of aservo-motor piston 22 in the proper direction to regulate the speed ofthe engine.

The pilot valve sleeve 2| is tightly fitted into a central verticalcylindrical bore 30 in a central portion of the power case whichcompletely surrounds the valve sleeve. The valve sleeve has acylindrical axial bore 3| which is open at both ends of the sleeve andin which various land portions of the pilot valve plunger are slidablyfitted and enabled to rotate while maintaining respective lateralportsof the sleeve sealed, as will be apparent. The plunger has two mainlands 25 and 26. The lower land 25 normally seals ports 28 of the pilotvalve sleeve (open to constant pres- I sure at the bore IT) withreference to the central bore of said sleeve. The upper land 26 normallyseals ports 29 of the pilot valve sleeve (open to the sump) againstcommunication with the central bore of the sleeve. A neck portion 35 ofthe pilot valve plunger maintains an open space between the valveplunger and valve sleeve which; communicatesat all times with a duct 36which, in turn, communicates freely with the lower end portion of theservo-motor cylinder, i. e. below the enlarged portion 31 of theservo-motor piston 22. The ports 28 of the sleeve which are normallyblocked by the land 25 communicate freely at all times with theservo-motor cylinder ,above the piston portion 31 through a duct 38.

The reduced upward end 39 of the servo-motor piston slidably closes theupper end of the servomotor cylinder and reduces the effective area ofthe servo-motor piston relative to the lower eifective area of thepiston, so that, with the same pressure admitted to the cylinder aboveand below the piston portion 31, the piston moves upwardly. l The pistonhas a power connection (regulating rod 40) extending downwardly out ofthe servo-motor cylinder block through a suitable sealing ring in a headmember 42 to enable regulation of the governed engine.

Downward movement of the servo-motor piston reduces and eventually cutsofi power input to the engine; and upward movement admits and increasessuch power input.

When the pilot valve plunger 20 is moved downwardly from its normal(illustrated) position, the land 25 opens the ports 28 to theinterior ofthe valve sleeve 2!, whereupon constant pressure from the bore l1 aroundthe sleeve is admitted to the duct 36 past the neck 35 of the valveplunger; and the servo-motor piston is raised due to the areadifierential of said piston.

When the pilot valve plunger is raised, the land 261by opening the ports29 to communication with the interior of the valve sleeve 2l dumpsoperating fluid from the servo-motor cylinder below the piston portion3'! to the sump through the duct 36, valve sleeve bore 3| and ports 29;and constant pressure from the bore I! through the duct 38 to the upperside of the pis- 0 wall portion around the flyton portion 31 then causeslowering of the servomotor piston.

The pilot valve plunger is maintained in the position shown, holding theservo-motor piston against movement, during normal operation of theengine, by reason of the operation of a flyball mechanism including aspeeder spring 5| and fly-balls 52 pivoted on a rotary ball head 53. Thefly-ball arms 54 bear upwardly at their" inner ends on a thrust member55 rigid with the pilot valve plunger, tending to raise the plunger asthe speed of the engine increases; but (e. g.), so long as the load onthe engine remains constant at a given setting of the speeder spring,the downward force of the spring on the valve plunger holds said plungeragainst upward movement,-in other words in balanced position to maintainboth lands 25 and 25 in closing rclation to their respective ports.Friction of the ball-arm fingers on the thrust member 55 causes thepilot valve plunger to rotate with the ball head during the entireoperation of the governor.

The connection between the speeder spring and pilot valve plunger 20 maycomprise an antifriction bearing assembly as in my Patent 2,219,229,which enables free rotation of the pilot valve plunger and non-rotationof the speeder spring.

The ball head 53 is journaled for rotation on a reduced upper endportion 56 of the pilot valve sleeve 2|. A depending hub portion 51 ofthe ball head which surrounds said portion 56 of the valve sleeve hasgear teeth 58 which mesh with a driving gear not shown on a verticalshaft, the lower end of which is drivingly rigid with the pimp gearwhich cooperates with the pump gear in said patent. The ball head 53 hasa circular balls which supports a sleeve 63 extending upwardly aroundthe flyballs and having an inturned flange 64.

Isochronousoperation of the governor requires primary and secondarycompensation, as is well known. The compensation system shown herein isessentially the same as that of the above identified patent andreference is directed to said patent for a more complete discussion ofthe same than given herein. Primary compensation is efiectedhydraulically as a function of servomotor piston movement; and restrainsthe axial movement of the pilot valve in its operation to initiatemovement of the servo-motor piston, thus preventing overtravel of saidpiston'both in reducing and increasing power input to the engine.

For primary compensation, fluid is moved in a compensation fluid duct 10which extends through various parts essentially the same as in my saidpatent. A hollow piston H fixed to the upper end of the servo-motorblock 3 operates in an axial bore 12 of 'the servo-motor piston 22 so asto serve as an actuating compensation pump in increasing and decreasingpressure at a space 13 below the pilot valve sleeve 2! and within theclosed lower end of the bore 30 of the power case. The compensationfluid duct 10 is normally kept full of operating fluid from the sumpthrough lateral holes 14 in a sleeve 74' (above servo-motor) the bore ofwhich sleeve has restricted-communication with the compensation duct 10at the upper end of the hollow piston 7|. The holes 74 are openoutwardly to the sump in the speeder case. I

When load on the engine drops the fiy-balls move outwardly, thus raisingthe pilot valve This ball head drive is the same as shown .or the rackbar in the relative adjustment of parts plunger. As the pilot valveplunger is moved upwardly from its normally centered positioninitiatinga downward or power input reducing movement of the servo-motorpiston-suction on the fluid in the compensation fluid duct tends toevacuate the space 13' below the pilot valve sleeve. This acts,hydraulically, yieldingly to restrain the upward movement of the -pilotvalve plunger, by virtue of a receiving compensation piston 15 connectedto the pilot valve plunger by means of a coil spring 16 capable ofimparting reversible restraining action on the plunger and capable ofcausing the piston I5 to turn with the valve plunger in the valvesleeve. The restraint (primary compensation) is only temporary because.as soon as the servo-motor piston starts to move downwardly, fluidbegins to leak into the compensation duct (secondary compensation) fromthe sump at holes I4 and th restricted communication thereof with thecompensation duct. The rate of leakage is regulated by an adjustableneedle valve pin 18 between the holes 14 and the compensation duct. Thespace between the receiving compensation piston I5 and the pilot valveplunger communicates freely with the sump space of the power case.

Upon increase of load, resulting in a lowering movement of the pilotvalve plunger, the reverse of the above described action takes place.The resulting upward or power-input-increasing movement of theservo-motor piston moves fluid in the compensation fluid duct [0,raising or tending to raise the receiving compensation piston 15,thereby to restrain the lowering movement of the pilot valve. Secondarycompensation (leakage through the restriction at the needle valve 18)removes the restraining action of the compensation piston I5 on thepilot valve plunger as the speed is brought back to normal; but thedirection of fluid leakage is reversed. Fluid leaks from duct 10 intothe sump.

The above described arrangement in general is the same as that of myPatent 2,219,229, and the operation thus far is also essentially thesame as in said patent.

Speed adjustment A speed control lever 80 extends diagonally of thespeeder case in a horizontal plane as shown, by Fig. 2. The lever has anadjustable-trunnion connection with the speeder spring in the form of ablock 8| (cylindrical sleeve) pivoted on aligned pins 82 which arecarried by spaced portions of the lever, and anadjustable screw 83 inthe block which bears downwardly on the speeder spring and may be lockedin place in the block as by a nut 84 engaging the block. The right handend of the speed adjusting lever 80 is supported-by a horizontal shaft88 mounted in the speeder case as on pivot bolts 89 (Fig. 2), the

lever 80, as shown, being suspended from the shaft by a link 85pivotally carried on a mounting assembly 88 concentric with the axis ofthe shaft. The mounting assembly shown includes parts I60 and I88 whichare unessential so far as the invention claimed herein is concerned-I60being a pinion adapted to be turned by teeth on a rack bar I6I supportedas at I62 and extending to the upper end of the servo-motor piston 22,being held in contact with said piston by a spring I64. The verticalmotion of the rack bar. as fully explained in the parent application,can be made to change the elevation of fulcrum of the speedadjustinglever (for speed droop adjustment) but said elevation will not bechanged by said motion 88 and I illustrated.

I Power head As shown in Figs. 2 and 3 the end of the speed adjustmentlever 80 opposite the fulcrum (i. e. left end. Fig. 2) is pivoted to anupright stem 90 of a power head piston 9| which operates in a verticalcylinder bore 92 formed in the speeder case, a portion of which latter(240) may extend below the top of the power case as showrr in Fig. 1 toaccommodate the power head. The stem 90 is slidably guided for verticalmovement in a cap 93 closing the upper end of the power head cylinderbore 92. The left hand end of the lever 80 is bifurcated to straddle thestem 90 and is provided with axially aligned horizontal pins 94, theproximate ends of which pivot in a ring 95 clamped to the upper end ofthe power head piston stem 90.

The power head piston is actuated hydraulically and is controlled by afollow-up valve the stem of which is shown at 96 within an axial bore ofthe piston stem 90, so that the piston moves up and down with thevalve, 1. e. as the valve stem is moved up and down. The valve admitsfluid from a constant pressure source (described later) into operativerelation to the piston for movement of the latter up and down exactly asthe valve stem 96 is moved. The

valve requires very little power to operate it, and thus the powerrequired for changing speed, manually or by a Selsyn motor, may be madeindependent of the variable resistance of the speeder spring in opposingspeed adjustment. "Constant pressure is applied to the upper side of thepower head piston 9| (Fig. 3) to move the piston downwardly, through aduct comprising a vertical bore I00 (left Fig. 1) in the power casecommunicating with the bore I'l thereof, and bores in the speeder casecomprising diagonal bore IOI, vertical bore I02 and a horizontal boreI03. The latter is shown in Fig. 3 connecting the upper end of the powerhead cylinder 92 with the vertical bore I02. The same pressure isapplied to the lower piston face (larger) to move the piston upwardly aswill be shown presently.

The power head valve is a cylindrical plug I05 on the lower end of thevalve stem 08, which latter does not seal the bore 97 of the pistonstern abovethe plug, whereas the plug is in sealing relation to theportion of the bore in which it slides. The plug I05 normally blocks twolateral ports I01 and I08 in the stem of the power head piston 9|. Theport I0! communicates freely with the power head cylinder below thepiston 9| through a duct I09; and the port I08 communicates directlywith the effectively smaller cylinder above the piston. 9|. When theplug I05 is moved downwardly by the speed setting mechanism, fluid fromthe cylinder 92 below the piston 9I is vented to atmosphere along thevalve stem 96, i. e. between it and the piston stem 90, whereuponpressure applied above the piston (smaller effective area) moves thepiston downwardly until the plug again blocks the port I01. Similarlywhen the plug I05 is raised it unblocks the port I08 admitting constantpressure to the lower end of the power head cylinder 92, thus raisingthe piston to whatever extent the plug I05 has been raised and thenblocking the port I08, stopping further upward travel of the piston.

Power head operating mechanism For operating the power head valve stem96 there is provided, as shown in Figs. 2 and 3, a bell crank Hpivotally supported on a horizontal shaft III in the speeder case. Thebell crank has a horizontally extending bifurcated arm I I2 providedwith a pin and slot connection H3 with the upper end of the said valvestem. An upstanding arm H4 of the bell crank has a yielding lost motionconnection (compressible link, including a spring I I5 and bar I IS)with an arm H1, which latter is keyed to a speed adjustment shaft H8suitably mounted in the speeder case parallel to the shaft III and atthe right thereof (Figs. 1 and 2). The bar H6 is pivotally pinned to thearm H1 at H9 and has a slot I slidably embracing a pin I2I on the bellcrank arm H4.

A clamping means I33 holds the arm I on the shaft H8. The shaft H8 maycarry an adjusting arm I30 having an operating wheel I and mechanism(not shown) connecting the wheel with a fixed quadrant bar I31 forangular adjustment of said shaft. A friction detent spring I on the armslides against the quadrant bar.

For increased speed adjustment the shaft H8 is rotated counterclockwiseas viewcd.in Fig. 1; and by virtue of the yielding lost motionconnection constituted by the spring H5, slot I20 and pin I2I the shaftI I8 cannot, upon turning of the shaft to increase speed-as at startingof governor operationbe moved so forcibly as to strain or break the armsH2, H4 or H1. The danger of such breakage occurring arises-from the factthat, until operating fluid pressure is built up in the hydraulic systemby the gear pump or otherwise, the power head piston is oillockedagainst downward movement.

To enable the relationship between turning of the shaft I I8 andadjustment of the speeder lever to be changed, a slot I24 (Fig. 1) isprovided in the upstanding arm H4 of the bell crank I I0, and the pinI2I can be locked in various positions along the arm I I4 thus changingthe angle through which the bell crank (and consequently the lever 80)will swing with a. given angular movement of the adjusting shaft H8. Thepin I2| has a clamping nut I2|a which is readily accessible through thetop of the speedercase.

Booster servo Shown at the left in Fig. 3 and located at the left inFig. 2 is a cylinder block portion 240 of the speeder case portion whichcontains the power head etc. previously described. Fig. 1, at the left,also shows part of the fluid duct system associated with the mechanismabout to be described. The booster-servo is for enabling air pressurefrom the starting air line of a Diesel engine to be used to insure thebuilding up of adequate pressure and supply of operating fluid in thegovernor during the operation of starting the engine, or previously.

- As shown in Fig. 3 the block portion 240 of the speeder case(hereinafter for convenience block 240) is bored upwardly from thebottom at 24I to a point near the top to receive a piston 242 having animperforate partition 243 between its ends; a downwardly projectinghollow cylinder portion 244 below the partition, and an upwardlyprojecting hollow cylinder portion 245 above the partition. The piston242 is normally forced downwardly, by a strong spring 246 in the upperpart of the cylinder bore 24I, against a pluglike member 241 fixed tothe block 240 and which nearly closes the lower end of the cylinderbore. The member 241 l. .s an axial bore 250 leadin therethrough andhaving an enlarged entrance portion threaded to receive an air pipeconnector fitting (not shown) of the starting air line. Pressure in suchlines is usually several hundred pounds. An upper cylindrical portion ofthe pluglike member 241 constitutes a fixed piston mating with the lowercylinder portion 244 of the piston 242. A cup shaped flexible sealingelement 252 is secured to the fixed piston 241, so that air admittedthrough the bore 250 thereof will raise the hollow piston 242,compressing the spring 246.

Assuming the upper part of the cylinder bore 24I contains hydraulicfluid, the air line pressure will force such fluid out of the upper endof the block 240 through a duct 253 formed by intercepting bores in thetop wall of the block 240 as clearly shown. The duct 253 (of. Figs. 1, 2and 3) leads to the constant pressure space I1 etc. of the hydraulicsystem of the governor as through a vertical bore 254 (see Fig. 1) andcheck valve chamber 255part of bore I02which latter communicates withthe duct comprised of bores I00 and I M (Fig. 1) already described. Thecheck valve chamber 255 has a spring pressed ball 251 therein operativeto prevent loss of pressure from the constant pressure chambers (I1etc., including power head cylinder 92) of the governor after startinghas been accomplished.

The booster-servo obtains hydraulic fluid from the speeder case portionof the sump through a duct comprising interconnected bores in thespeeder case; 260', 26I, 262 and 263 (Fig. 2 particularly), past agravity seated ball check 264 (Fig. 1) in the bore 262. The bore 263intercepts the discharge duct 253 in the top of the booster cylinderblock. The ball check 264 prevents return flow of fluid to the sump fromthe booster cylinder when the booster-servo piston is raised instarting.

In the event the governor stands idle for some time the spring loadedpressure accumulators will ordinarily force most of the fluid out of theconstant pressure spaces into the sump. In such event subsequentoperation of the booster-servo piston would be resisted only by theunloaded or nearly unloaded accumulator springs. Also if fluid happenedto be low in the speeder case portion of the sump at the time thebooster-servo piston 242 previously descended to draw a new supply offluid from that portion of the sump and the sump supply failed to supplyfluid there would be nothing but air in the upper part of the cylinder 2to damp the upward movement of the booster-servo piston on the nextactuation. In either event damage to the upper boosterservo cylinderhead portions can be prevented by the present arrangement (Fig. 3), viz:

The upper cylinder portion 245 of the boosterservo piston slidablyreceives a dash pot plunger 265 having a small hole 268 extendingtherethrough to a downwardly open counterbore 261 of the Plunger. Acompression spring 268 resting on the partition 243 extends into thecounterbore 261 and operates, whenever necessary, to draw fluid into thechamber below the plunger through the hole 256 until the spring hasbecome fully extended. The hole 266 of the plunger is aligned with thevertical portion of the duct 253 so that the hole 266 cannot be sealedby engagement of the plunger with the top of the cylinder bore 24I. Across slot in the top of the plunger 265 prevents the plunger fromblocking exit of hydraulic fluid from the booster-servo cylinder 2 tothe duct 253 at the completion of the upward stroke of the booster-servopiston. .In the fully expanded position of the spring the plunger 2'65stands a short distance above the top rim.

of the upper cylinder portion 245 of the boosterservo piston. Thus whenair is applied to raise the booster-servo piston and the pistonencounters little or no resistance except that afiorded by the pring 246the impact of the booster-servo piston is cushioned by discharge ofhydraulic fluid from the dash pot.

To prevent oil from entering the air starter line where it might causean explosion if allowed to be carried into the engine along with thestarting air, a vent hole is provided at 210 in the member 241 whichserves as 'the fixed air piston. The illustrated position of the ventalso prevents air which may leak past the sealingcup 252 from enteringthe hydraulic fluid of the governor along the outside of the hollowpiston 242.

Starting air admitted to the chamber between the fixed and movablepistons 24'! and 242 can be bled out of said chamber at a ball checkvalve 212, Fig. 3, having a ball 213 which moves outwardly against aseat 214 in a sleeve 215 (overcoming the force of the ball spring 216)when air is applied to the line and which is pushed away from the seatby the spring when the air pressure finally drops say to around 75# persq. in.

While the booster-servo mechanism is described above as operated by thestarting air line of a Diesel engine and the governor mechanism is showna adapted for speed governing of such engine, it will be understood thatthe boosterservo mechanism may be operated by any kind of fi'lldpressure and that the governor, by appropriate adaptation as Well knownin the art, can be used for other purposes than speed regulation andcontrol.

I claim:

1. In a speed governor wherein a weighing element drivingly connected toa rotary part of a mechanism to be governed controls regulation of suchmechanism through a hydraulic relay, means operable by such rotary partto maintain a supply of hydraulic fluid under operating pressure duringoperation of the governor, said means including a reservoir 'for thefluid, a hydraulic booster piston and cylinder in upright position, thetop of the cylinder having hydraulic fluid connections with saidreservoir and said piston having a spring to force it downwardly in thecylinder capable of drawing a booster reserve supply therefrom andmaintaining the reserve supply separate from the reservoir, and a motoroperable by elastic fluid associated with the lower end of the boosterpiston and operable to cause said piston to rise in its cylinder andpump hydraulic fluid of the reserve supply to the reservoir for creatinginitial pressure upon tarting of the governor operation.

2. In argovernor for engines adapted to be started by compressed air,said governor employing a hydraulic fluid operated regulation sys tem, acasing for the governor providing a nor mal supply for hydraulic fluid,a substantially upright booster servo cylinder bore in the casing, aduct formed in the casing leading into an upper end portion of thecylinder bore and communieating with said normal fluid supply to chargethe cylinder bore with hydraulic fluid from the system for subsequentredelivery to the system through said duct, a booster servo-piston inthe cylinder bore, a spring acting downwardly on the piston to cause thepiston normally to occupy a lower end portion of the bore when thecylinder bore is charged, an air cylinder bore extending upwardly in thepiston from the lower end of the piston, a fixed plug element in thelower end of the cylinder member and having a piston portion slidablyfitting the air cylinder bore, a duct in the piston portion of the plugelement lengthwise thereof to supply air as from an enginestarting airsupply to the air cylinder bore of the booster servo-piston foractuating the latter during starting of such engine, and a vent in oneof said elements communicating with the lower end of the boosterservo-cylinder for preventing intercharge of hydraulic fluid and airpast the main cylinder surface and the air cylinder surface.

3. In a governor, weighing means responsive to a force factor of amechanism orapparatus to be governed, a source of hydraulic pressuredependent upon sustained operation of the mechanism or apparatus to begoverned, hydraulically-actuated regulating means for said mechanism orapparatus, a pilot valve operatively connected to said weighing meansfor controlling the supply of hydraulic fluid from said source to saidregulating means, a casing, a bi-directional hydraulic motor mechanismin said casing operatively connected -to and constituting an adjustingmeans for said weighing means and supplied with fluid from said source,and means for supplying said weighing-means-adjusting hydraulic motormechanism with operating hydraulc fluid during incipient as well assustained operation of the mechanism or apparatus to be governed, saidlast-mentioned means comprising a hydraulicpressure boosting mechanismin said casing alongside said hydraulic motor mechanism and operative,in response to a starting condition of said mechanism or apparatus, toboost the hydraulic pressure derived from said source and delivered tosaid motor mechanism to a value suflicient to operate said motormechanism at the inception of operation of said mechanism or apparatusto be governed. Y

ALBERT KALIN.

